diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 0000000..4c2f513
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,64 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "lldb",
+            "request": "launch",
+            "name": "Debug unit tests in library 'rustwallet'",
+            "cargo": {
+                "args": [
+                    "test",
+                    "--no-run",
+                    "--lib",
+                    "--package=rustwallet"
+                ],
+                "filter": {
+                    "name": "rustwallet",
+                    "kind": "lib"
+                }
+            },
+            "args": [],
+            "cwd": "${workspaceFolder}"
+        },
+        {
+            "type": "lldb",
+            "request": "launch",
+            "name": "Debug example 'test'",
+            "cargo": {
+                "args": [
+                    "build",
+                    "--example=test",
+                    "--package=rustwallet"
+                ],
+                "filter": {
+                    "name": "test",
+                    "kind": "example"
+                }
+            },
+            "args": [],
+            "cwd": "${workspaceFolder}"
+        },
+        {
+            "type": "lldb",
+            "request": "launch",
+            "name": "Debug unit tests in example 'test'",
+            "cargo": {
+                "args": [
+                    "test",
+                    "--no-run",
+                    "--example=test",
+                    "--package=rustwallet"
+                ],
+                "filter": {
+                    "name": "test",
+                    "kind": "example"
+                }
+            },
+            "args": [],
+            "cwd": "${workspaceFolder}"
+        }
+    ]
+}
\ No newline at end of file
diff --git a/Cargo.lock b/Cargo.lock
index 1faedd1..126ea16 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -26,6 +26,12 @@ version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "904dfeac50f3cdaba28fc6f57fdcddb75f49ed61346676a78c4ffe55877802fd"
 
+[[package]]
+name = "bitcoin_hashes"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90064b8dee6815a6470d60bad07bbbaee885c0e12d04177138fa3291a01b7bc4"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -1202,6 +1208,7 @@ version = "0.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b7649a0b3ffb32636e60c7ce0d70511eda9c52c658cd0634e194d5a19943aeff"
 dependencies = [
+ "bitcoin_hashes",
  "rand 0.8.5",
  "secp256k1-sys 0.6.0",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 4568023..0e2376d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,7 @@ crate-type = ["staticlib", "lib"]
 [dependencies]
 anyhow = "1.0.65"
 openssl = { version = "0.10.41", features = ["vendored"] }
-secp256k1 = { version = "0.24.0", features = ["rand"] }
+secp256k1 = { version = "0.24.0", features = ["rand", "bitcoin_hashes"] }
 serde = { version = "1.0.145", features = ["derive"]}
 serde_json = "1.0.85"
 shamir_secret_sharing = "0.1.1"
diff --git a/examples/test.rs b/examples/test.rs
index 5b962de..4630522 100644
--- a/examples/test.rs
+++ b/examples/test.rs
@@ -7,7 +7,7 @@
 use std::ffi::CStr;
 //use rustylib::gen::{CWallet};
 use rustwallet::{
-    fetch_cwallet, free_cwallet, generate_cwallet, save_wallet, CWallet,
+    fetch_cwallet, free_cwallet, generate_cwallet, save_wallet, sign, CWallet,
 };
 
 fn main() {
@@ -23,6 +23,7 @@ fn main() {
         println!("---- fetching the saved wallet to be exposed to C-side ----");
         let fetched = fetch_cwallet();
         print_wallet(&fetched);
+        sign();
 
         free_cwallet(wallet); // 对应 generate_cwallet()
         free_cwallet(fetched); // 对应 fetch_wallet()
diff --git a/src/lib.rs b/src/lib.rs
index a6d239e..f78e33a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -67,6 +67,25 @@ pub unsafe extern "C" fn fetch_cwallet() -> CWallet {
         Ok(w) => return convert_to_cwallet(w),
     };
 }
+#[no_mangle]
+pub unsafe extern "C" fn sign() {
+    match wallet_impl::Wallet::retrieve_keys("wallet.json") {
+        Err(_) => {
+            println!("error sign");
+        }
+        Ok(w) => {
+            match w.sign("111") {
+                Err(err) => {
+                    println!("error sign: {:?}", err);
+                }
+                Ok(sig) => {
+                    println!("sig result: {:?}", sig);
+                }
+            }
+
+        } 
+    };
+}
 
 unsafe fn convert_to_cwallet(rwallet: Wallet) -> CWallet {
     // 转换Rust字符串数据为C的字符串并移交ownership
diff --git a/src/wallet/wallet_impl.rs b/src/wallet/wallet_impl.rs
index 4749c01..d2c977c 100644
--- a/src/wallet/wallet_impl.rs
+++ b/src/wallet/wallet_impl.rs
@@ -1,11 +1,16 @@
 use anyhow::Result;
+use secp256k1::ecdsa::Signature;
 use secp256k1::rand::rngs::OsRng;
-use secp256k1::{PublicKey, SecretKey};
+use secp256k1::{PublicKey, SecretKey, Message};
+use secp256k1::hashes::sha256;
 use serde::{Deserialize, Serialize};
 use std::io::BufWriter;
+use std::str::FromStr;
 use std::{fs::OpenOptions, io::BufReader};
 use tiny_keccak::keccak256;
 use web3::types::Address;
+use std::str;
+use core::fmt::Write;
 
 pub fn generate_keypair() -> (SecretKey, PublicKey) {
     let secp = secp256k1::Secp256k1::new();
@@ -20,6 +25,7 @@ pub fn public_key_address(public_key: &PublicKey) -> Address {
     Address::from_slice(&hash[12..])
 }
 
+
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Wallet {
     pub secret_key: String,
@@ -30,8 +36,16 @@ pub struct Wallet {
 impl Wallet {
     pub fn new(secret_key: &SecretKey, public_key: &PublicKey) -> Self {
         let addr: Address = public_key_address(&public_key);
+        println!("secret key: {:?}", secret_key);
+        let mut s = String::with_capacity(2 * 32);
+        for i in &secret_key.secret_bytes() {
+            write!(s, "{:02x}", *i);
+        }
+        println!("{:?}", s);
+
+        
         Wallet {
-            secret_key: format!("{:?}", secret_key),
+            secret_key: s,
             public_key: public_key.to_string(),
             public_address: format!("{:?}", addr),
         }
@@ -56,4 +70,16 @@ impl Wallet {
         let wallet: Wallet = serde_json::from_reader(buf_reader)?;
         Ok(wallet)
     }
+
+    pub fn sign(&self, msg: &str) -> Result<Signature> {
+        let secp = secp256k1::Secp256k1::new();
+        let message = Message::from_hashed_data::<sha256::Hash>(msg.as_bytes());
+        println!("secret key str: {:?}", self.secret_key);
+        println!("message: {:?}", message);
+        let pk = SecretKey::from_str(&self.secret_key).expect("32 bytes, within curve order");
+        println!("secret key: {:?}", pk);
+        // let sig = secp.sign_ecdsa(&message, &pk);
+        let sig = secp.sign_ecdsa(&message, &pk);
+        Ok(sig)
+    }
 }
diff --git a/wallet.json b/wallet.json
index 968c6e4..9e363dd 100644
--- a/wallet.json
+++ b/wallet.json
@@ -1,5 +1,5 @@
 {
-  "secret_key": "SecretKey(#d3bfbf530f3823ca)",
-  "public_key": "026c148cde34fead14781bcea7c51a0e9384a7356f3093af1c10d0734da07cf243",
-  "public_address": "0x4b1636199d65f39c9a4be4a6423b5982db2f1f3b"
+  "secret_key": "4877e4466ed17b3fa3c5040760a8401bc26565126bd611fdbd903a4652a26b37",
+  "public_key": "03a0b65abcf64937afff82590b1580add0a3a344e00f209de388dd1378f8162419",
+  "public_address": "0x5f88990fa8ad8c6e8c33929a685fadec146102f4"
 }
\ No newline at end of file